In agriculture, no-till planting practices, in which the planting process is adapted to minimize soil disturbance to leave organic matter from the previous crop grown in a field in place, are commonly applied in the production of various crops. Some furrow openers, or drills, use rotatable discs to fracture the soil into furrows of disturbed soil into which seed can be placed. It is known to form a seed bed, or shelf or ledge, above the furrow bottom using a scraper positioned to also clean the disc, thereby allowing for seed placement on this shelf to avoid the placement of seed amongst the higher level of residue or debris that may be found at the furrow bottom. However, without careful seed placement on the narrow shelf, seeds may drop from the seed shelf deeper into the furrow, potentially causing poor or inconsistence emergence of the crop resulting from the fallen seeds being disposed too far beneath the surface. This improper placement of the seeds may result from seeds bouncing from a well-formed seed shelf after discharge from the seed tube or from a poorly defined seed shelf that is not adequate to receive or support and retain the seeds.
Conventional no-till planting practices sometimes include the process of making a separate pass over a field to deposit fertilizer either on the surface or in the top soil. In order to eliminate the need for additional passes, openers have been developed that both place the seed on a seed shelf formed by the opener and deposit fertilizer into the field.
Canadian Patent Application No. 2,125,533 teaches an opener having a fertilizer tube mounted in proximity to a disc to deposit fertilizer into the bottom of the furrow formed thereby. A seed tube is supported rearward of the disc and includes a hoe opener mounted to the front side thereof to form a shallow seed shelf in an upwardly directed face of the furrow onto which seed is delivered for positioning above and to the side of the fertilizer. The soil coming off the back edge of the disc falls down over the furrow in a self-closing action, so that when the seed shelf is formed by the trailing hoe opener, the seed deposited thereon cannot fall deeper into the furrow.
However, it is desirable to provide a disc opener which can help prevent the seed from falling from the seed shelf deeper into the furrow without the need for an additional opening implement carried rearward of the furrow-forming disc.
U.S. Pat. No. 7,152,539 teaches an embodiment of an opener having a scraper defined by a body that extends away from the disc and then rearward to situate a seed tube between the body and the disc. The bottom edge of the scraper body extending away from the disc forms a seed shelf in the side of the disc-formed furrow onto which seed is deposited by the seed tube. Liquid fertilizer is delivered under pressure to a nozzle disposed on a side of the body opposite feed tube to inject the fertilizer into the soil on a side of the seed shelf opposite the furrow bottom. This arrangement is limited to use with liquid fertilizer, as the pressure thereof is relied upon to deliver the fertilizer to the desired depth in the soil. Also, it may still be possible for the seeds to fall into the furrow bottom toward the disc.
Therefore, it is desirable to provide a disc opener which facilitates the deposit of seeds and either of liquid and granular fertilizers in a single pass without the need for an additional opening implement carried rearward of the furrow-forming disc.